hello guys in this video we'll be discussing about the voltage source inverter fed indexer motor Drive okay so here we can call it as vsi also it is nothing but voltage source inverter now I will be discussing motor points all things you have to mention if it comes in examination okay so here we have transmit transistor inverter fed we are considering this motor Drive using what transistors so let me just tell you what is this voltage source inverter you can see inverter is there so inverter so what BSI does this is the first point you have to mention what vsi it is it basically converts the DC Supply to variable frequency Supply inverter what does it do it basically converts a DC to AC same thing so variable frequency Supply so this is the first point you have to mention that what does BSI do converting what this is applied to variable frequency Supply okay now here we are discussing about this diagram is basically about the PSI employing transistors transistors are being involved correct all the transistors six stances namings also you can see tr1 TR4 TR6 like that six transistors have been used okay now instead of transistors we can use any self-commutated devices we can use any self-commutated devices now what all devices will come under this now the category wise will study so this self-community device can be characterized into three levels low power levels medium and high so low powerless mode switch can be used and medium power levels igbt and power transistors can be used so and high power levels G2 and igct can be used okay this all things can be considered now moving forward with the third point that is nothing but here vsi can be operated in two ways okay one is chapter wave and another one is pwm what is pwm it is pulse speed modulation pulse width modulation so this can be vsi that is voltage source inverter can be used or can be operated as SEPTA wave inverter or we can operate it as what pulse width modulation modulated inverter okay modulated inverter so in these two ways you can mention so here you can see the diagrams two diagrams has been specified here so vsi thread motor drives can be operated in two ways one is step to wave inverter and another one is pwm inverter okay now what happens in when this vsi is operated in step to be able what will happen now we are considering here many switches many transistors [Music] so in this stances we can see many names are given okay each specified names are given and this transistors must be switched on with some certain time difference right so this can be switched on at A T by T by 6 time difference if you see this transistors whatever suppose tr1 is the TR4 is there something like that in sequence it must be straw switched on and with the time difference of T by 6 and each transistor must be kept on for duration at least for duration it should be turned on at least for the duration of T by 2 okay so each time difference between the transistor to B should be T by 6 and each transistor should be on for at least what T by 2 time what is t t is nothing but the time period of one cycle okay so this all things comes under what step to wave inverter like that you can just specify so coming to the next part what all things you can mention here okay so here you can make these diagrams this is nothing but voltage source inverter controlled induction motor drives here we are considered see these two things are related to six step inverter six step inverter okay stepped wave inverter comes under that category these two are for the pwm inverter now when the supply when the supply is DC If You observe here the supply is DC then in order to convert the input for the inverter see we need here input for the inverter that has been transferred right so here Chopper has been used which basically converts the fixed voltage input Supply DC Supply to variable voltage DC Supply right variable voltage or DC Supply okay so that will be the input given to water six term inverter now what is the use of this capacitor this is nothing but a large electrolytic filter capacitor C we can just mention it as large electrolytic filter capacitor C now this has two purpose okay so this C is being used for two purpose where it is connected to the DC link okay so it has been used to to purpose to make the inverter operation independent of rectifier or Chopper or anything diode Bridge or anything so in order to make the inverter operation see here we have inverter right pwm as well as stepword in order to make the operation independent this is the first purpose operation independent what independent operation it will do basically job inverter independent of it will operate independently without of the influence of this Chopper control rectifier or diode Bridge okay and second operation is nothing but second purpose is to filter out the filter out the harmonics filter out whatever the harmonics is there fluctuations is there in DC link voltage whatever the fluctuations or anything is there that is being filtered out okay so harmonics to filter out the harmonics so first up first purpose was to make inverter pwm or six step inverter to operate independently independently of what Chopper control rectifier or anything diode Bridges anything like that okay okay coming back to this one so first thing is nothing but whenever DC supplies that we are converting into using Chopper to in order to convert it to variable voltage DC Supply and it is given to the inverter next whenever the AC Supply is there we have to use control rectifier so what does the rectifier do retriever basically AC to DC it will convert right so we'll get here input voltage as DC for the six step inverter okay now here this is this is one case where we are using six step inverter step to wave inverter now second case we have pwm in this also whenever the DC supplies is there we have no need to use any kind of rectifier job or anything directly we can give it to the PW now here AC Supply is there we have to convert it to DC in order for that for that we have to use what diode Bridge diode Bridge we are using okay so in order to convert AC to DC basically diode Rectify okay so in order to get in order to bug the pwf inverter so this is all things you can mention and one more if you want you can mention here one more formula which is nothing but the inverter output line and phase voltage that formula is given by the Fourier series that is VAB is equal to 2 root 3 by pi VD VD is nothing but the input whatever the voltage you are giving sine Omega t minus 1 by 5 sine Pi Omega T minus 1 by 7 sine 7 Omega t Plus 1 by 11 sine 11 Omega t plus so on like this it goes on okay this is one kind of equation you can write this is basically what inverter [Music] output line face output line and phase voltage okay this you can mention itself so VD you can see it over here here we have VD okay right this speed this is nothing but the VD thing [Music] [Music]